Quadratic Formula Lesson 2

Question 1

Bronze example:

Solve the quadratic equation below to 3sf.

4x2 + 8x + 2 = 0

Answer 1

First:

-8 + square root (8)2 - 4 (4) (2)
2 (4)

-8 - square root (8)2 - 4 (4) (2)

Finally:

x = - 1.71(3sf) for minus

x = - 0.293(3sf) for add

Question 2

A quadratic equation in the form of …

Answer 2

ax2 + bx + c = 0

Question 3

A quadratic equation in the form of ax2 + bx + c = 0 can be solved by …

Answer 3

using the discrminant

b2 -4ac

Question 4

What is the discriminant of the quadratic formula …

Answer 4

b2 - 4ac

Question 5

If b2 - 4ac is a ? number we won’t get a ? solution

Answer 5

negative … real

Question 6

A solution can also be called a …

Answer 6

root

Question 7

Why do we use the discriminant?

Answer 7

To quickly determine whether the quadratic equation has any solutions (roots)

Question 8

Silver example:

Given the quadratic equation below:

3x2 + 3x + 2 = 0

Does the equation have roots?

Answer 8

b2 - 4ac

First:

a =3
b = 3
c=2

Second:

3(squared) - 4 x 3 x 2

= 9 - 24

Third:

= -15

Finally:

The discriminant is negative and therefore there is no root.